Identifying Molecular Markers Associated with Resistance to Fire Blight Disease in Apple

Approach:
Gene sequences associated with susceptibility or resistance to fire blight will be identified by bioinformatic and functional genomic approaches including subtractive hybridization, cDNA-AFLP analysis, and bioinformatic analysis within the USDA-ARS fire blight resistance program, as well as, an extensive apple sequence database available at HortResearch, New Zealand. These sequences will be used by HortResearch to develop molecular markers, such as single nucleotide polymorphisms (SNPs) and simple sequence repeats (SSRs, also known as micro-satellite markers). The molecular markers will then be used to screen segregating mapping populations of 'Robusta 5' x 'Malling 9' or 'Royal Gala' x A689 (at HortResearch) and 'Robusta 5' x 'Ottawa 3' (at USDA-ARS) to determine map location, and whether the sequences co-locate with quantitative trait loci (QTLs) for fire blight resistance.